1. Field Of The Invention
This invention relates in general to the field of rotating toys. More specifically it relates to the yo-yo.
2. Description Of Prior Art
The term yo-yo was derived from the equivalent meaning of come-come in the native language of the Philippines where the toy is thought to have evolved from an ancient weapon. Stones with a groove around the periphery have been found in archaeological sites. It is believed that the groove was carved in order to secure twine or strip of leather to the stone. A warrior or hunter could thus throw the stone, quickly recover it and throw it again. Archaeologists have shown that over many years the groove had been made deeper, presumedly at first to allow the twine to be all wound within the groove for the convenience of carrying it. The user would not have thrown the stone from the wound-up condition to wound an animal or an enemy because this would have resulted in primarily rotational speed of the stone instead of linear speed. The first to have carved a deep groove would have allowed the stone to drop while holding the end of the twine only for the purpose of letting the string out. When the stone reached the end of twine and rotated back up the string the come-come was discovered.
In the 1920s a Phillipino named Pedro Flores invented the sleeping yo-yo. Instead of tying the string to the axle, he looped the string around the axle to allow the yo-yo to spin freely in the loop at the end of the string without returning up to the user's hand. This free spinning is referred to as sleeping. The sleep condition is used to perform many trick maneuvers The yo-yo may be returned to the users hand from the sleep condition by a slight jerk of the string. The phenomenon that takes place here is that: Following the jerk, the string becomes slack for a moment and allows the semi-tight loop to wind up on the axle, increasing the frictional drag as more string is wound around the axle and becomes wedged in the gap beteen the inertial masses.
There have been numerous efforts to improve yo-yo performance. A novelty search of prior art relating to the yo-yo discovered the following U.S. patents:
______________________________________ U.S. Pat. No. Classification Inventor ______________________________________ 1,419,402 6/1922 Mosher 2,591,954 4/1952 46/61 Madsen 2,629,202 3/1953 46/61 Stivers et. al. 2,645,881 7/1953 46/61 Frangos 2,676,432 4/1954 46/61 Field 2,773,328 12/1956 46/61 Fraenkel et. al. 2,975,547 3/1961 46/61 Greve 3,081,578 3/1963 46/72 Mosher 3,175,326 3/1965 46/61 Isaacson 3,184,885 5/1965 46/61 Gibson 3,256,635 6/1966 46/61 Radovan 3,444,644 5/1969 46/61 Sayegh 3,805,443 4/1974 46/61 Duncan 4,130,962 12/1978 46/61 Ennis 4,290,225 9/1981 46/61 MacCarthy 4,318,243 3/1982 46/61 MacCarthy 4,332,102 6/1982 46/61 Caffrey 4,437,261 3/1984 46/61 MacCarthy 4,442,625 4/1984 46/61 MacCarthy ______________________________________
A close approach to the disclosed construction and function of the present invention was not observed in the above cited patents. Perhaps of most merit are patents: U.S. Pat. No. 3,256,635 to Radovan claiming radial flutes that grip the string. U.S. Pat. No. 4,130,962 to Ennis claiming cone shaped protuberances to aid the griping of the string. U.S. Pat. No. 2,629,202 to Stivers et. al. claiming varies on the axle surface adjacent to the central polished zone and friction disks with an adhesive characteristic ridgedly mounted on the axle to aid the binding of the string in the gap. These devices do not relate to the initiation of string wind-up. These devices make contact with the string only after the string has made several wraps around the axle and has spread out laterally. This is stated so by Stivers where he refers to the string ". . . shifted into contact therewith . . . " and ". . . expansion of the loop incident to relaxed tension upon the string." These devices cause the string to fray and shorten string life. The present invention utilizes extended smooth lapper disks where the gap between them is adjustable to make a skimming contact with the cord. U.S. Pat. No. 3,175,326 to Isaacson claims a ball bearing to reduce friction between the string and the shaft to attain longer sleep times. In order to return the yo-yo to the hand, strands of the string must become caught in the circumferential gap between the periphery of the bearing and the rotating body. U.S. Pat. No. 4,332,102 to Caffrey claiming use of a bearing and a centripitally activated clutch to return the yo-yo to the hand. This invention demonstrates the dificulty of making a yo-yo with very low running friction and having the yo-yo reliably return to the hand at will. Both isaacson and Caffrey bearing inventions use a looped and twisted string.
The following improvements to yo-yo construction have been patented: U.S. Pat. No. 2,975,547 to Greve claims the two inertial masses mounted on a split pin, allowing the yo-yo to be assembled in different configurations. U.S. Pat. No. 3,081,578 to Mosher uses a hollow sleeve rotatably journaled on a shaft. The shaft is terminated on each end with an abutment. The abutment is used as part of a means of attachment to a finger to allow the user to grip the shaft with one hand while the string is pulled with the other hand to span the disks. The two inertial disks of this invention are fixed on the sleeve. The floating shaft of this invention is not functionally nor constructurally similar to the present invention. Mosher's invention also has bands of resilient material disposed around the outer maximum periphery of each of the disks for providing a cushioning effect to the disk. The purpose of the resilient material as stated is to cushion the disks--That is to protect the disk. The slight thickness and width of the resilient material is not an effective cushion for the hand. The design of the present invention allows sufficient thickness and width of resilient material to give the feel of catching a rubber ball as the yo-yo returns up the cord to the hand. U.S. Pat. No. 3,805,443 to Duncan Jr. claims the use of a rivet to rigidly clamp the inertial masses to a spool. There are no constructional nor functional equivalences between these inventions and the present invention. U.S. Pat. No. 2,676,432 to Field claims an annular collar with a gap for fixing the string with a knot or flattened end. This is not a sleeping yo-yo. The collar is part of the rotating inertial masses and therefore is not equivalent to the yoke of the present invention.